Coyle, William
Wadsworth and Cengage Learning, 2013
Buku Teks SO
Wallwork, Adrian
Springer, 2016
Buku Teks
edited by Glenn T. Seaborg, Joseph J. Katz and Winston M. Manning
McGraw-Hill, 1949
Buku Teks SO
Gibaldi, Joseph
The Modern Language Association, 2003
Buku Referensi
Gibaldi, Joseph
The Modern Language Association, 2003
Buku Teks SO